HD Picture not filling up the entire screen of my HDTV

dondem

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Original poster
Oct 4, 2006
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I wonder if anyone has noticed this. I currently have a Panasonic TH-65PF9UK 1080P plasma that has been set to do 1:1 mapping (no TV scaling). I have a VIP-211 box that is set to output 1080i connected to a video processor that converts it to 1080P.

I noticed that most HD channels leave about a quarter of an inch to the left side of the screen blank.
The only HD channels that fills up the entire screen are:
1. all HDNET channels
2. all ESPN channels
3. FOX and ABC

Voom channels leave about a quarter of an inch blank in the bottom of the screen.

Why is this happening? Does this mean that these channels are not broadcasting in full 1920x1080 resolution? Or is this a problem with the satellite box?
 
You might hit the "format button" on your remote see if that takes care of the issue.
 
If changing the format output from the 211 doesn't change it, what happens when you remove the video processor from the mix?
 
Format is normal and I don't want to stretch or zoom it. Also I have tried connecting the box directly to the display and the same result. I can easily fix this by turning the 1:1 pixel mode off (scaling on) on the display. But I want my signal as pure as possible no scaling other than the video processor.
 
What is the amount of overescan on your plasma? If it is 2% or less you are going to have these problems sometimes, different channels broadcast slightly different sized picture, overscan usually takes care of people not seeing the edge of the picture, but if it is set to low this could happen.
 
I have the exact same issues on my Westinghouse 1080p monitor. It is connected via HDMI directly from my 622. I also see a dotted white line under the ticker on ESPN HD
 
I wonder if anyone has noticed this. I currently have a Panasonic TH-65PF9UK 1080P plasma that has been set to do 1:1 mapping (no TV scaling). I have a VIP-211 box that is set to output 1080i connected to a video processor that converts it to 1080P.

I noticed that most HD channels leave about a quarter of an inch to the left side of the screen blank.
The only HD channels that fills up the entire screen are:
1. all HDNET channels
2. all ESPN channels
3. FOX and ABC

Voom channels leave about a quarter of an inch blank in the bottom of the screen.

Why is this happening? Does this mean that these channels are not broadcasting in full 1920x1080 resolution? Or is this a problem with the satellite box?
I have 0% overscan and I can confirm his observations. Also on VOOM channels you will see a white and red vertical line in the lower right black area. It is not a problem and most HD broadcast have some "garbage" in the edges. VOOM may use this as a watermark method.

For reference here is a picture with 0% overscan.
overscan00.jpg
 
I don't know how you get the percent overscan but I did calibrate it using DVE and it is centered. I can increase the resolution horizontally/vertically in the video processor and this corrects the problem but don't want to do that. I'm keeping it the way it is at 1920x1080P @ 60Hz. I was just curious if this was normal or not.

So I guess different stations have different picture sizes.
 
DVE has an overscan pattern on it, test it on the same input you have your 211 connected to. Do not use the overscan pattern on the HDnet test pattern as it is incorrect.

Think of a computer monitor, you want to adjust it so the desktop goes just to the edges, push it to far & you have overscan, to little & you have a black boarder(underscan). A tv monitor is slightly different, you want some overscan so the picture fills the whole screen, but not so much that you are missing info in the picture.

My TV has the overscan set about 2%, I had it set at 0 but I got some annoying jagged edges or data info on the sides or bottom of the picture sometimes. Even at 2% when playing a video game I get black boarders on the sides, the larger the picture the game has to fill up the more processing power it needs, If I wanted no boarders on video games I wopuld have to have the overscan at about 5%, so I can deal with the boarders on the games, at least they have a clean line.

http://scanline.ca/overscan/

http://www.hometheaterhifi.com/volume_6_3/essay-video-resolution-july-99.html

http://www.mastersofcinema.org/reviews/03lookingbeyond.htm
 
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it's the programs on voom themself that have the black bar on them

I think they explanation I've got before is those programs were shot with DV cameras
 
DVE has an overscan pattern on it, test it on the same input you have your 211 connected to. Do not use the overscan pattern on the HDnet test pattern as it is incorrect.

Think of a computer monitor, you want to adjust it so the desktop goes just to the edges, push it to far & you have overscan, to little & you have a black boarder(underscan). A tv monitor is slightly different, you want some overscan so the picture fills the whole screen, but not so much that you are missing info in the picture.

My TV has the overscan set about 2%, I had it set at 0 but I got some annoying jagged edges or data info on the sides or bottom of the picture sometimes. Even at 2% when playing a video game I get black boarders on the sides, the larger the picture the game has to fill up the more processing power it needs, If I wanted no boarders on video games I wopuld have to have the overscan at about 5%, so I can deal with the boarders on the games, at least they have a clean line.

http://scanline.ca/overscan/

http://www.hometheaterhifi.com/volume_6_3/essay-video-resolution-july-99.html

http://www.mastersofcinema.org/reviews/03lookingbeyond.htm

I don't have that much issue in the top and bottom portion of the screen. I do see it happen with ESPN but it doesn't bother me that much. The thing that I see in most HDTV broadcast is that thin black bar on the left side of the screen. I think I set overscan to 0% using DVE. If I move the image to the left the right edges become distorted. Since I like to keep it 1:1 mapping and keep the resolution to 1920x1080 so I'll leave it alone.
 
I have the next HDNet test pattern set to record (in a couple of days I think). I will post pictures of it with 0% and other rates anyone wants. This will make it easy to tell how much overscan your display has.
 
Also, look at your TV's zoom scale. And the setup of the Dish box for what format to use. You are probably set for a 4:3 in that menu (not format button, but your setup).
 
A few years ago I went into my Toshiba SDTV's service menu and adjusted the overscan. This was helpful as it reduced the distance between the scan lines and made the picture a bit sharper ... although it also made it a bit "smaller" in that it was no longer showing me the center 32" out of a 34" virtual picture. So all objects shrunk a bit.

However when I did this, and adjusted it down to 0%, I had the same problems that you describe. I could see the "edges" on some channels. So I had to tweak it up a bit to stop this from occuring. It started out at 5-6% and I think I ended up around 2%. I was happy with the final results.
 
Your 1080p display is probably displaying the image correctly. 1080 is REALLY 1088 lines (it has to be a multiple of 16), the last eight lines are black in the ATSC spec. It is also possible that the channels in question are broadcasting several pixels in black on the left.

My CRT projector shows everthing right up to the picture's edge and several OTA stations havea line across the top (above the closed caption encoding( and a line down the left side (several pixels outside the actual image).
 
The HDnet overscan test is somewhat inaccurate, as the numbers do not represent a percentage
I will still record it and you can see the exact percentage of overscan applied by the menu of my VP50 (top right in red). This way you can determine your sets approximate overscan.

overscan7.6.jpg

 

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